1993 ford econoline 150 has misfire and black

There are two or three things that can cause black smoke on a six cylinder van.a bad fuel pressure regulator is one.it is located on the fuel rail. it is silver and has red vacuum line attached to it. remove the hose and see if fuel comes out of the regulator, if so replace the regulator. next a bad map sensor can cause black smoke. it is located under the hood.bolted to the firewall. its a black square plastic object with a wire connector attached to it, also it may have a vacuum hose attached to it. if it has a hose see if the hose is broken. otherwise just unplug the map sensor see if it changes the idle. if it does than chances are the sensor is good. you could have a bad injector also. disconnect spark plug wires one at a time. if one of them does not change than that injector maybe bad. thats all i can help with. good luck.